So let me pose this question: What sets "literary fiction" aside from all other genres? Shouldn't all fiction, no matter what the subject matter, hold the above characteristics?

I think the answer lies in the first attribute. Critically acclaimed. Universally accepted pieces aren't just rare, they don't exist. For every classic there are those that will pick a hole in the plot, rip the main character to pieces, shit upon the theme. If you cut "critically acclaimed" out of the aspects of literary fiction, you have, well, just good fiction.

It doesn't matter if it's a civil war drama or a horror novel, a depression-era mystery or a contemporary comedy, good fiction should have a slamming plot, characters that breathe, and universal struggles that everyone recognizes and feels.